XRT72L13 Datasheet, PDF (262/370 Pages) Exar Corporation – M13 MULTIPLEXER/CLEAR CHANNEL DS3 FRAMER IC

XRT72L13
M13 MULTIPLEXER/CLEAR CHANNEL DS3 FRAMER IC
REV. P1.0.6
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PRELIMINARY
FIGURE 74. BEHAVIOR OF THE "TERMINAL INTERFACE" SIGNALS BETWEEN THE XRT72L13 AND THE TERMINAL
EQUIPMENT (DS3 MODE 6 OPERATION)
Terminal Equipment Signals
TxInClk
DS3_Nib_Clock_In
DS3_Data_Out[3:0]
Tx_Start_of_Frame
Nibble [1175]
Nibble [0]
XRT72L13 Transmit Payload Data I/F Signals
TxInClk
TxNibClk
TxNib[3:0]
TxNibFrame
Nibble [1175]
Nibble [0]
Note: TxNibFrame pulses high to denote
DS3 Frame Boundary.
DS3 Frame Number N
DS3 Frame Number N + 1
Sampling Edge of the XRT72L13
How to configure the XRT72L13 into Mode 6
1. Set the "NibInt" input pin "high".
2. Set the "TimRefSel[1:0] bit-fields (within the
"Framer Operating Mode" Register) to "1X" as
illustrated below.
OPERATING MODE REGISTER (ADDRESS = 0X00)
BIT 7
BIT 6
BIT 5
BIT 4
Local Loop-
back
Mode
R/W
0
Line Loop-
back
Mode
R/W
0
Internal LOS
Enable
R/W
1
RESET
R/W
0
3. Interface the XRT72L13, to the Terminal Equip-
ment, as illustrated in Figure 73 .
4.2.2 The Transmit Overhead Data Input Inter-
face
BIT 3
BIT2
BIT 1
BIT 0
Interrupt
Enable
Reset
R/W
1
Frame Format
R/W
0
TimRefSel[1:0]
R/W
R/W
1
x
Figure 75 presents a simple illustration of the "Trans-
mit Overhead Data Input Interface" block within the
XRT72L13.
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